He's ingrained in the warring human culture his father forewarned. In any case - from the perspective of creating Kotal Kahn, the timing is obviously perfect. After the 2011 reboot, we just hope it was thought about, rather than glossed over. Perhaps the Osh-Tekk were forsaken by the Elder Gods, had no godly representation, or was a "realm" of Outworld in the traditional sense, rather than the otherworldly MK sense. If there's more story here, we welcome it. Given the stretch of time between Mortal Kombat tournaments, it's not unreasonable to think Outworld was monitoring other interests whilst pursuing Earthrealm through sporadic tournaments, but we've certainly never thought of it that way, and the conquest is not depicted with any sense of the Elder Gods' rules.
The rules of the Elder Gods' tournament were in place for quite some time before Shao Kahn and Goro conquered the golden realm. We know Goro defeated Earthrealm's last great champion: The Great Kung Lao. This places the story around 1519 - meaning the conquest of Osh-Tekk was close to Goro's first tournament win, possibly after (depending on the elastic determination of "the present"). As fate has it, Kotal Kahn arrives in The Amazon jungle at the same time as the Spanish conquistadors.
Sticklers for the original series fiction will remember Goro as the undefeated champion of Mortal Kombat for 500 years. Where things start to break down a little is in the timeline. It's a familiar concept for strengthening a young warrior - popularly identified with the Spartan agoge - and a fine wrinkle to tie him to our world. He gained this mantle through an Osh-Tekk rite of passage called the "Realmwalk", which sent him into the harsh, warring world of Earthrealm. This portal stone answers the question raised in the previous chapter: why is Kotal Kahn so casually visiting the Special Forces of Earthrealm? As it turns out, he has deep ties to our world through the use of this stone! As it turns out, Kotal Kahn doesn't just resemble an Aztec deity - he is one! Much as we've learned Raiden is known by other names to other cultures (such as Haokah) Kotal Kahn is identified with the Aztec war god Buluc. It was a gambit that allowed Kotal K'etz to retain his treasures - chief among them a "portal stone". A culture that, as it turns out, succumbed willingly after their bitter defeat. We've always known Shao Kahn conquered and merged many realms into his empire of Outworld, so it's nice to go back to a time before the conflict with Earthrealm, to see another of the fallen cultures. Shao Kahn and the forces of Outworld reintroduce its ruler Kotal K'etz to the forgotten concept of defeat. It starts with the conquest of a golden realm called Osh-Tekk, many ages ago. In many ways, it's reminiscent of the klassic video game character bios, spread out to show what it also tells. The epic backstory is condensed into a simple but effective episode. It's also a very effective way to get the root of one of the most interesting new characters introduced to Mortal Kombat in a very long time! Kotal is character we've been eager to learn more about since his E3 2014 unveiling, and abrupt introduction to the comics, in chains, during Chapter 4. It's a small acknowledgement of the fusion of cultures that is now stronger than ever. Long time fans know the ties between MK and comics.
It's an incidental detail, but it's fun to see the comic book tradition of the "secret origin" incorporated into Mortal Kombat. Note: The following review contains spoilers! If you haven't read digital Chapter 6 (or Mortal Kombat X #2 in print) you should visit DC Entertainment to purchase unread chapters for 99c each! Mortal Kombat X: Blood Ties continues with a sharp turn away from the previous chapter's cliff hanger ending - toward a solo spotlight in a mini-story aptly titled "Kotal Kahn: Sekret Origin".